1. Field of the Invention
This invention relates to a method and apparatus for the detection of chemiluminescence, e.g., the luminescent assay of an analyte in a sample. Preferably apparatus and methods are provided in the rapid production of a permanent photographic record of such chemiluminescent, e.g. by the use of a POLAROID film.
2. Description of the Prior Art
Luminescence may be simply defined as the emission of visible or invisible radiation which is the result of a chemical reaction. In chemiluminescence the source of the energy is a chemical reaction. A special form of chemiluminescence is bioluminescence, which is found in the biological systems, in which a catalytic protein increases the efficiency of the luminescent reaction.
Chemiluminescent reactions systems generally require an oxidant (for example, hydrogen peroxide); a catalyst, (for example microperoxidase, heme, hemoglobin or cobalt); and a chemilumingenic compound.
Large number of substances can be accurately determined by means of chemiluminescent reactions. Such reactions generate light, the intensity of which is directly proportional to the concentration of the reacting substances. If during the reaction the luminescent substance is in excess, the light intensity is directly proportional to the concentration of the substance investigated in the sample; thus a simple measurement of light intensity yields an accurate determination of the sample concentration. The radiation can be generated in any of the visible, ultraviolet and infrared spectral regions.
Conventionally, the known test systems have been of the type which include in the reagent composition one or more chromogenic redox indicators which are either directly responsive to the analyte to be determined, or are combined with and react to the product of an analyte responsive system. The known sensitivity of luminescence assays and their applicability to analytical intermediates, e.g. ATP, NAD(H) and peroxide, have led to the use both of chemiluminescence and bioluminescence as analytical tools in clinical chemistry.
Until recently, most luminescence measurements have been made by using individually constructed apparatus or commercial equipment modified to meet the peculiar requirements of luminescence. Commercially available instruments which have been modified include photometers, fluorometers and scintillation counters.
Another approach which has been taken in efforts to measure luminescence is the exposure of photographic film to light emitted by the luminescent reaction. Chemiluminescent reactions have been monitored on film to detect enhancers, inhibitors, catalysts and oxidants in various systems.
Another suggestion was to inject a sample and chemiluminescent reagents into a sealed container surrounded by photographic film and then measuring the film exposure as a function of concentration.
Moreover, other processes are known according to which a recording which has already been produced image-wise is converted into luminescence images by toning processes or by printing processes.
The patent literature is replete with patents relating to methods and apparatus for assays using chemiluminescence.
U.S. Pat. No. 2,865,744, patented Dec. 23, 1958, by J. S. Friedman et al. was directed to fluorescence in photographic emulsions and to a duplicating process using such fluorescence. The patentee provided a process of preparing a direct duplicate from a transparent original by exposing with blue light through the original, a photographic material carrying, on a transparent support, a silver halide emulsion containing a sensitizing dye capable of increasing the fluorescence of the emulsion, for a specified period of time. Then the process involved exposing with blue light through the exposed intermediate printing material, a duplicating material carrying, on a suitable support, a panchromatic emulsion while interposing a yellow filter between the intermediate and the duplicating material. The yellow filter absorbed all of the blue light but transmitted the fluorescent light emitted by the intermediate material to be recorded upon the panchromatic emulsion. The latent image in the duplicating material was developed in a black and white developer to form a duplicate picture of the original.
Coffman, U.S. Pat. No. 3,239,406, disclosed a chemiluminescent tape useful as a marker. Upon exposure to air, the tape chemiluminesced for different periods of time and at different levels of illumination depending upon the type and amount of chemiluminescent composition incorporated in the structure. The tape comprises at least one layer or surface which was adhesive to other surfaces and which had at least a surface impregnated with a chemiluminescent composition containing at least one peraminoethylene and a strippable film overcoat or removable envelope to protect the peraminoethylene composition from exposure to oxygen prior to use.
U.S. Pat. No. 3,795,489, patented Mar. 5, 1974 by A. Warrick et al, related to a chemiluminescence reaction chamber in which a gaseous sample mixture and gaseous reactant mixture were brought together at one edge of a shallow, disc-shaped, reaction chamber. The exhaust opening of the reaction chamber was located diametrically from the mixture inlet. A light-transmitting element formed one wall of the reaction chamber and the reacting gases passed through the reaction chamber in a plane substantially parallel to the light-transmitting element.
U.S. Pat. No. 3,801,324, patented Apr. 2, 1974, by H. R. Postal, was directed to a non-conflicting, double-image photographic film employing both silver-based and photofluorescer compounds. The invention resided in the provision of a photographic film element having photographic medium and optically-active medium for providing identifying indicia. The optically-active medium was a compound which was converted to a fluorescent state by short wave ultraviolet radiation and which could be read by longer wave ultraviolet.
U.S. Pat. No. 3,923,462, patented Dec. 2, 1975, by L. A. Cavanagh related to photographic detection and integration of light emitted from luminescent reactions. Cavanagh disclosed an automated apparatus for the detection of ozone in ambient air. A sample of air was passed through a light-tight enclosure where it reacted with a material, e.g. Rhodamine B, which luminesces in the presence of ozone, or a material which normally luminesces (e.g. in black light) and was quenched in the presence of ozone. Photographic film was positioned in the enclosure and was spaced apart from the chemiluminescent system. The film was in exposed relationship to the luminescent reaction inside of the light-tight enclosure.
U.S. Pat. No. 4,181,650, issued Jan. 1, 1980, to C. I. Maier, Jr., related to a method for the rapid, accurate, quantitative or qualitative determination of biologically-active substances at extremely low concentrations. The patentee provided a determination of the presence and amount of a specific organic substance (ligand) that will form a complex with a macromolecule (antibody) which could be made by means of a reagent obtained by binding a chemiluminescent substance to the ligand to be assayed. The addition of a limited amount of a substance (antibody) having receptors for the ligand together with the chemiluminescent-labeled ligand to the fluid to be assayed resulted in a competitive reaction between the ligand present in the fluid and the chemiluminescent-labeled ligand for the limited number of receptor sites. Under equilibrium conditions, the amount of chemiluminescent-labeled ligand bound to the antibody was related to the amount of unlabeled ligand in the solution being assayed, and was determined by isolating the antibody and measuring its chemiluminescence, or by isolating and measuring the amount of free labeled-ligand remaining.
U.S. Pat. No. 4,231,754, patented Nov. 4, 1980, by P. O. Vogelhut, related to a chemiluminescent analytical device. The patentee provided a test device for determining an analyte in a sample. The test device included a unitary solid carrier incorporated with a first reagent system responsive to the presence of the analyte to produce a reaction product. A second reagent system was responsive to the presence of that reaction product to produce luminescence. The test device was said optionally to include a photoresponsive layer physically associated with the carrier means and which was responsive to light produced by the chemiluminescent system.
U.S. Pat. No. 4,396,579, patented Aug. 2, 1983, by H. R. Schroeder et al, related to a luminescence detection device for quantitatively detecting an analyte in a liquid sample. The device included a compartment having, along a primary axis, opposite end portions, a first of which was for introduction of fluid reagents and sample into the compartment and the other of which formed a light-transmissive aperture of predetermined size, the compartment being suitable to hold a composition which luminesces in response to contact with analyte-containing sample. A closure was provided in the first end portion for admitting a cannula, so that fluid could be introduced into the compartment, and for closing the compartment. A photoresponsive, imaging layer was also provided, along with means for associating the photoresponsive imaging layer and the compartment such that the photoresponsive imaging layer was positioned, preferably substantially perpendicular to the primary axis of he compartment, at a predetermined distance from the end portion forming the aperture so as to be exposed to light emanating therefrom. Means were provided for preventing exposure of the photoresponsive image layer to ambient light. Light emitted from the aperture exposed a zone of the imaging layer which it contacted. The amount of light emitted was proportional to the amount of analyte in the sample. Even at low analyte concentrations, the light exposed a "base zone" of the imaging layer.
U.S. Pat. No. 4,429,060 patented Jan. 31, 1984, by Y. Uasuda et al, related to a competitive immunochemical measurement of plural trace components involving spectral sensitizing dye labels. The patented method included labeling an antigen or antibody with a spectral sensitizer having an absorption region of a wavelength longer than the intrinsic absorption wavelength of silver halide (preferably longer than 500 nm) which was adsorbed onto silver halide grains in order spectrally to sensitize the silver halide grains. The labelled substance was immunochemically reacted with an antibody or antigen. Either the reaction product of the unreacted antigen or the antibody was brought into contact with silver halide. The silver halide was exposed and developed. The quantity of the resulting developed silver or colored dye was then measured as optical density.
U.S. Pat. No. 4,543,308, patented Sept. 24, 1985, by H. J. Shumann et al, related to a photographic recording process. The patentee provided a technique for electronic image recording in one or more colors of a photographic recording material. The photographic material having, in at least one layer, photo-sensitive silver halide and a compound capable of luminescence was image-wise exposed and developed to produce a latent luminescence image. The image information contained in the latent luminescence image was scanned photoselectively by a luminescence spectroscopic process and was recoded electronically in the form of monochromatic luminescence signals.
Other patents of general interest include the following:
Canadian Pat. No. 475,984 which related to the concept of the use of a film, to detect substances present in small proportions in a carrier medium.
Canadian Pat. No. 1,067,740 which related to the concept of typing blood using a camera and a film, whereby the camera can take a composite image forming a photographic record of the typing results on a plate.
Canadian Pat. No. 1,072,387 which related to the concept of providing a movable sheet film holder for recording multiple images first appearing in a CRT tube.
Canadian Pat. No. 1,136,467 which related to the concept of providing a multi-image film cassette holder with automatic positioning for recording images originally appearing on a CRT tube.